在 VB.NET 中检查空的 TextBox 控件

Check for empty TextBox controls in VB.NET(在 VB.NET 中检查空的 TextBox 控件)

问题描述

我在 VB.NET 中有一个 Form 应用程序.

Ive got a Form application in VB.NET.

我在一个表单上有很多文本框(大约 20 个).无论如何要一次检查它们是否为空，而不是写出大量代码来单独检查每个，例如

I have many text boxes on one form (about 20). Is there anyway to check them all at once to see if they are empty instead of writing out a massive line of code to check each one individually such as

If txt1.text = "" Or txt2.text="" Then
    msgbox("Please fill in all boxes")

这似乎还有很长的路要走?

That just seems like a long way around it?

推荐答案

你也可以使用 LINQ:

You could also use LINQ:

Dim empty =
    Me.Controls.OfType(Of TextBox)().Where(Function(txt) txt.Text.Length = 0)
If empty.Any Then
    MessageBox.Show(String.Format("Please fill following textboxes: {0}",
                    String.Join(",", empty.Select(Function(txt) txt.Name))))
End If

有趣的方法是Enumerable.OfType

查询语法相同(在 VB.NET 中更易读):

The same in query syntax(more readable in VB.NET):

Dim emptyTextBoxes =
    From txt In Me.Controls.OfType(Of TextBox)()
    Where txt.Text.Length = 0
    Select txt.Name
If emptyTextBoxes.Any Then
    MessageBox.Show(String.Format("Please fill following textboxes: {0}",
                    String.Join(",", emptyTextBoxes)))
End If

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